What you need to know: Changes in Trump's revised immigration order

President Trump's revised executive order suspending the U.S. refugee program and entry to the U.S. from several mostly Muslim countries included a number of changes compared with the original.

Here’s what you need to know:

Iraq removed from list. The executive order still imposes a 90-day suspension of entry to the United States for nationals of several mostly Muslim countries. Iraq, however, has been removed from the original list. The new list covers six countries: Sudan, Syria, Libya, Somalia, Yemen and Iran. According to the administration, the Iraqi government agreed to increase cooperation with the U.S. government with regard to vetting travelers to the U.S.

Valid visas stand. The order clarifies that foreign nationals from the six countries who already had valid visas as of Jan. 27 will not be affected.

Syria treated the same. The new order still calls for a temporary suspension of all refugees from any country while measures are put into place to vet. But the new order drops language regarding an "indefinite suspension" of Syrian refugees. They will no longer be singled out, addressing an issue the courts had with targeting Syrian refugees. According to the revised order, returning refugees are an exception.

Green card holders exempt. The new order makes clear that legal permanent residents are not affected.

Security review. In the first 20 days, DHS will perform a global, country-by-country review of identity and security information that each of the six countries provides to support U.S. visa and immigration determinations – countries then have 50 days to comply with U.S. requests to update or improve the quality of that information, prior to issuing a travel visa.

Rollout in public. The last time, the president signed the document without much media fanfare. This time, Secretary of State Rex Tillerson, Secretary of Homeland Security John Kelly, and Attorney General Jeff Sessions introduced the revised executive order in a media briefing.

New effective date. The Trump administration said the new Executive Order is effective at 12:01 a.m. EST on March 16.

Fox News' John Roberts contributed to this report.

Brooke Singman is a Politics Reporter for Fox News. Follow her on Twitter at @brookefoxnews.